EL CAJON, Calif. (AP) — Dozens of demonstrators protested Wednesday outside a suburban San Diego police station after a black man who reportedly was acting erratically at a strip mall was shot and killed by an officer when, according to authorities, he pulled an object from a pocket, pointed it and assumed a "shooting stance"

The Rev. Shane Harris said the man's sister had called 911 to report her brother was acting out and made clear he had mental issues.

"There were real issues with his mental health and that was part of the conversation," Harris said in an interview.

One officer fired an electronic stun gun and another officer simultaneously fired his firearm several times, El Cajon Police Chief Jeff Davis told reporters at a news conference late Tuesday night. Davis would not say what the object was, but acknowledged it was not a weapon.

Before police announced the death, dozens of protesters gathered at the shooting scene, with some claiming the man was shot with his hands raised. Police disputed that and produced a frame from a cellphone video taken by a witness that appeared to show the man in the "shooting stance" as two officers approached with weapons drawn.

The fatal shooting happened just weeks after black men were shot and killed by police in Tulsa, Oklahoma, and in Charlotte, North Carolina, where violent protests broke out.

Candles and flowers were left Wednesday at the scene of the Tuesday afternoon shooting, near bloodstains on the pavement.

The man shot often hung around the strip mall and frequently seemed "agitated but he was never aggressive toward me," said Victor Hauer, who works at a nearby convenience store and sometimes bought the man food or gave him a few dollars.

The protest in El Cajon Tuesday was angry but peaceful. Several dozen people, most of them black, gathered and some cursed at officers guarding the scene. They chanted "black lives matter!" and "hands up, don't shoot!"

Davis urged the community to remain calm and said the investigation will be thorough.

"This will be transparent," he said. "This will be looked at by multiple sets of eyes, and not just ours."

Police said they were called to the mall shortly after 2 p.m. by the sister of a man in his 30s who said he was "not acting like himself" and walking in traffic. They say the man refused "multiple" orders to take his hand from his pocket, then was shot after pulling out the object.

When detectives arrived, police say a female witness came forward and voluntarily provided cellphone video of the incident. Authorities released the single frame from it but not the video. El Cajon officers do not wear body cameras.

Other videos quickly surfaced showing the aftermath. In one posted to Facebook, an unidentified woman is heard telling police at the scene that the man was ordered to take his hand out of his pocket.

"I said: 'Take your hand out your pocket, baby, or they're going to shoot you.' He said 'no, no, no,' " the woman said. "When he lifted his hand out ... he did have something in his hand but it wasn't no gun, and that's when they shot him."

Another woman on the video wearing hospital-style work clothing identified herself as the man's sister. She shrieked and cried, telling officers that she had called them to help her brother, who she described as mentally ill.

"I just called for help, and you came and killed him," she said.

Michael Ray Rodriguez was among witnesses who said the man had his hands in the air. He said that he was driving from his apartment complex past the shooting scene and saw a shirtless black man with his hands raised.

The officer "let go of the trigger and shot him again and again," Rodriguez told the San Diego Union-Tribune.

El Cajon is about 15 miles northeast of San Diego and has a population of about 100,000.

It is 69 percent white and 6 percent black, according to 2010 census figures, and has become a home for many refugees fleeing Iraq and, more recently, Syria.